KR100704271B1 - Switching power supply - Google Patents

Abstract

 Reduce power loss and improve conversion efficiency.

The voltage of rectifying and smoothing the commercial AC power supply 10 is supplied to the oscillation drive circuit 14 and the switching circuit unit 15. The switching circuit section 15 constitutes a half bridge circuit, and the output point is grounded through the primary winding L1 of the resonant capacitor 16, the choke coil 17, and the insulated converter transformer 18. The converter transformer 18 is provided with a secondary winding L2 for obtaining a + B voltage and high voltage windings L6 to L14 for obtaining a high voltage output voltage EHT. In addition, the voltage variation of the high-voltage output voltage EHT is supplied to the oscillation drive circuit 14 through the resistors 20 and 21, the control circuit 22, and the photo coupler 23, and the switching circuit section 15 is controlled. In addition, the saturable reactor 32 is connected in series to the secondary winding L2. By controlling the inductance of the saturable reactor 32, the + B voltage taken out from the secondary winding L2 is controlled.

Description

Switching power supply

1 is a configuration diagram of a first embodiment of a switching power supply apparatus according to the present invention.

2 is a diagram for explaining the main portion thereof.

3 is a block diagram showing the overall configuration.

4 is a configuration diagram of a second embodiment of the switching power supply apparatus according to the present invention.

5 is a configuration diagram of a third embodiment of the switching power supply apparatus according to the present invention.

6 is a diagram for explaining the main portion thereof.

7 is a configuration diagram of a fourth embodiment of the switching power supply apparatus according to the present invention.

8 is a diagram for explaining another configuration.

9 is a configuration diagram of a conventional switching power supply.

10 is a diagram for explaining the operation.

11 is a waveform diagram for the invention.

12 is a characteristic diagram for explanation.

Fig. 13 is a block diagram showing the overall configuration of a conventional apparatus.

* Explanation of symbols on the main parts of the drawings

10. AC AC 11. Diode bridge rectifier circuit

12. Smoothing capacitors 13. Resistors                 

14. Oscillating drive circuit 15. Switching circuit part

Q1, Q2. Switching elements D1 and D2. Damper diode

16. Resonant Capacitor 17. Choke Coil

18. Converter transformer L1. Primary winding

L2-L15. Secondary winding D6 to D15. diode

19. Output capacitor 20,21. resistor

22. Control circuit 23. Photocoupler

24-27. Rectification circuit (diode) 28-31. Smoothing circuit (capacitor)

32. Saturable Reactor 33.34. resistor

35. Reference voltage 36. Inverting comparison amplifier

37. Control transistor 38. Smoothing capacitor

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching power supply suitable for use in a computer display monitor or a large television receiver for displaying a high resolution video signal using, for example, a cathode ray tube. Specifically, for example, in a display monitor or a television receiver using a cathode ray tube, a plurality of voltages including high voltage generation can be efficiently generated.

As a power supply device used for a computer display monitor or the like for displaying a high resolution video signal, a device using an isolated switching power supply circuit, a horizontal deflection circuit, and a high voltage generating circuit has been conventionally used, for example, as shown in FIG.

That is, in Fig. 9, a commercial AC power supply 100 is connected to the smoothing capacitor 102 through the diode bridge rectifying circuit 101. The negative electrode terminal of the capacitor 102 is grounded, the positive electrode terminal is connected to the oscillation drive circuit 104 via the resistor 103, and the positive electrode terminal of the capacitor 102 is connected. It is grounded through the switching circuit part 105 which becomes a series circuit of these switching elements Qa1 and Qa2. These switching elements Qa1 and Qa2 are driven to alternately conduct at a predetermined frequency by the oscillation drive circuit 104.

In addition, the switching circuit section 105 constitutes a half bridge circuit, the positive electrode terminal of the capacitor 102 is connected to the drain of the switching element Qa1, and the source of the switching element Qa2 is grounded. The damper diodes Da1 and Da2 are connected in parallel to the switching elements Qa1 and Qa2, respectively. The connection point between the source of the switching element Qa1 and the drain of the switching element Qa2 is connected to the primary winding La1 of the resonant capacitor 106, the choke coil 107, and the insulated converter transformer 108. Grounded through.

As a result, a resonant current inverted in accordance with the oscillation frequency of the oscillation drive circuit 104 described above flows through the primary winding La1 of the converter transformer 108, and a so-called current resonant converter power supply circuit is constructed. do. That is, in this circuit, the basic operation of the primary side of the converter transformer 108 is as shown in FIG. In Fig. 10, the equivalent circuit when the switching element Qa1 is turned on by the drive pulse from the oscillation drive circuit 104 shown in a of the figure shows that the b and the switching element Qa2 of the figure are turned on. The equivalent circuit at that time is shown in c of the figure.

When the switching element Qa1 is turned on, since the switch 201 corresponding to the switching element Qa1 is closed in the equivalent circuit of FIG. 10B, the DC voltage source 203 corresponding to the positive electrode terminal of the capacitor 102 is closed. And a series resonant circuit of the inductor 204 and the resistor 205 including the resonant capacitor 106, the choke coil 107 and the primary winding La1. A positive resonant current flows through the switch 201 using the DC voltage source 203 as a power source.

Next, when the switching element Qa2 is turned on, since the switch 202 corresponding to the switching element Qa2 is closed in the equivalent circuit of FIG. 10C, the resonant capacitor 107 and the inductor are passed through this switch 202. (204) A negative resonance current flows through the series resonant circuit of the resistor 205. In this manner, positive resonant currents are alternately generated in accordance with the drive pulses from the oscillation drive circuit 104, and alternating currents of a desired frequency flow in the series resonance circuit described above.

11 shows current waveforms flowing through the parts of the equivalent circuit shown in FIG. 11A and 11B show waveforms of currents IQ1 and IQ2 flowing through the switching elements Qa1 and Qa2, respectively. FIG. 11C shows waveforms of the resonant current I1 flowing through the series resonant circuit. Indicates. 12 shows the relationship between the resonant current I1 and the frequency f flowing through the series resonant circuit. In FIG. 12, f0 denotes a resonant frequency of the series resonant circuit of FIG. 10, and fsw denotes a repetitive operating frequency of the switching circuit portion 105 driven by the oscillation drive circuit 104. In FIG.

In this case, if the values of the resonant capacitor 106, the inductor 204, and the resistor 205 are set to C, L, and R, respectively, and the admittance is obtained as Z as the impedance of the series resonant circuit for each frequency (ω), The admittance (Y) is represented by equation (1).

On the other hand, the resonant frequency f0 of the series resonant circuit is expressed by equation (2).

Here, since the current I in Equation 1 is proportional to Y, the curve of FIG. 12 is used to represent the magnitude of the current I1 with respect to frequency using the maximum value of the resonance current at the resonance frequency f0. To give. The repetitive operating frequency fsw of the switching circuit section 105 serving as the switching elements Qa1 and Qa2 is set to move along the right side of the resonance curve, that is, to satisfy fsw> f0 at these frequencies.

Based on the above-described basic operation, the entire circuit operation of FIG. 9 will be described in detail. As the switching operation of the power supply circuit according to the circuit configuration of FIG. 9, the smoothing capacitor 102 is a rectifying current obtained by rectifying the commercial AC power supply 100 to be first introduced in the diode bridge rectifying circuit 101 as a charging current. The rectified smoothing voltage is generated at both ends of. The rectified smoothing voltage is used as an operating power source, and power is supplied to the oscillation drive circuit 104 through the resistor 103, and the driving pulses generated alternately in the oscillation drive circuit 104 are switching elements Qa1 and Qa2. Supplied to.                         

In addition, in the oscillation drive circuit 104 at the timing, for example, a positive driving pulse is supplied to the switching element Qa1, and a negative driving pulse is supplied to the other switching element Qa2 constituting the switching circuit section 105. Is supplied. As a result, when the switching element Qa1 is turned on and the switching element Qa2 is turned off, one of the resonant capacitor 106, the choke coil 107, and the isolation type converter transformer 108 is passed through the switching element Qa1. The positive resonant current is supplied to the series resonant circuit of the car winding La1.

In the oscillation drive circuit 104 at the next timing, a negative drive pulse is supplied to the switching element Qa1, and a positive drive pulse is supplied to the other switching element Qa2 constituting the switching circuit unit 105. . As a result, the switching element Qa1 is suddenly turned off, and the switching element Qa2 is turned on. As a result, a negative resonance current is supplied to the series resonant circuit of the primary winding La1 of the resonant capacitor 106, the choke coil 107, and the isolated converter transformer 108 through this switching element Qa2.

The converter transformer 108 is excited by the series resonant current obtained by repeating this operation. The alternating output voltage is taken out from the secondary windings La2, La3, La4, La5 wound on the secondary side of the converter transformer 108. In addition, these secondary windings La2, La3, La4, La5 respectively include rectifying circuits (diodes) 109, 110, 111, 112, and smoothing circuits (capacitors) 113, for extracting a DC voltage from an alternating output voltage. 114, 115, and 116 are connected.

In this way, in the secondary windings La2, La3, La4, La5 of the converter transformer 108, through the rectifying circuits 109, 110, 111, 112 and the smoothing circuits 113, 114, 115, 116, respectively. For example, a so-called + B voltage (voltage value E0), which is a power supply voltage of a horizontal deflection circuit or a high voltage generation circuit, and other voltages (voltage values E2, E3, E4) used as power supply voltages of each signal system circuit are taken out. .

Moreover, the so-called + B voltage which becomes the power supply voltage of the horizontal deflection circuit and the high voltage generation circuit obtained by the secondary winding La2 of this converter transformer 108 is performed as follows, for example. That is, for example, if the luminance of the image displayed on the cathode ray tube increases and as a result, the voltage fluctuates so as to increase the high voltage load or the horizontal amplitude of the image displayed on the cathode ray tube increases, the load of the + B voltage is reduced. Increases. As a result, the voltage value E0 of the + B voltage is intended to be varied so as to decrease.

After the voltage fluctuation is taken out of the voltage detection unit composed of the resistors 117 and 118, and error amplified in the control circuit 119, the switching circuit unit (I) through the photocoupler 120 for insulating the constant voltage control system. It is sent to the oscillation drive circuit 104 which performs frequency control and drive of the 105. The operating frequency of the drive pulse output from the oscillation drive circuit 104 is controlled in accordance with this voltage. As a result, the switching frequency fsw of the switching circuit portion 105 is lowered.

Here, in the above-described power supply circuit, the switching circuit section 105 is more than the resonance frequency of the series resonant circuit composed of the resonant capacitor 106, the choke coil 107, and the primary winding La1 of the insulated converter transformer 108. The switching frequency fsw is set high. Therefore, in this circuit, when the switching frequency fsw is controlled to decrease, the switching frequency fsw becomes close to the resonance frequency f0 of the series resonant circuit in FIG. 12, and as a result, the primary winding La1 By increasing the excitation current flowing through), constant voltage can be achieved.

On the contrary, if the brightness of the image displayed on the cathode ray tube decreases, and as a result, the voltage fluctuates so as to reduce the high pressure load or the horizontal amplitude of the image displayed on the cathode ray tube changes, the voltage value of the + B voltage ( E0) fluctuates to rise. For this reason, as described above, the control signal is sent to the oscillation drive circuit 104 through the photocoupler 120, and is controlled so that the operating frequency of the drive pulse output from the oscillation drive circuit 104 increases according to this voltage. . As a result, the switching frequency fsw of the switching circuit portion 105 is raised.

Therefore, when the switching frequency fsw is controlled to rise, the switching frequency fsw falls with respect to the resonance frequency f0 of the series resonant circuit in FIG. 12. As a result, the first order of the converter transformer 108 is reduced. By suppressing the excitation current flowing through the winding La1, constant voltage can be attained. At this time, other voltages (voltage values E2, E3, and E4) taken out from the secondary windings La3, La4, and La5 of the same converter transformer 108 also have a so-called cross regulation, so that the constant voltage can be approximately increased. do.

In addition, the + B voltage obtained in the secondary winding La2 of the converter transformer 108 in this manner is, for example, the horizontal oscillation drive circuit 122 and the horizontal output circuit (through the horizontal amplitude pin distortion correction circuit 121). 123 and a horizontal deflection yoke 124 is supplied to the horizontal deflection circuit. In addition, the + B voltage obtained by the secondary winding La2 of the converter transformer 108 is a high voltage composed of the high voltage oscillation driving circuit 125, the switching circuit portion 126, the control circuit 127, and the high voltage transformer 128. It is also supplied as a power source for the generation circuit.

Next, the high voltage generation circuit will be described. In Fig. 9, the high voltage generating circuit is composed of a current-type current resonant converter. The drain of the switching element Qa3 is connected to the + B voltage so that the two switching elements Qa3 and Qa4 constituting the switching circuit unit 126 form a half bridge circuit, and the source of the switching element Qa4 is grounded. do. Further, damper diodes Da3 and Da4 are connected between the source drains of the switching elements Qa3 and Qa4, respectively.

Also, at the connection point between the source of the switching element Qa3 and the drain of the switching element Qa4, a resonant capacitor 129, a choke coil 130, and a high voltage transformer 138 such as a flyback transformer FBT are provided. It is connected in series. The switching elements Qa3 and Qa4 are supplied with rectangular drive pulses having different polarities from each other in order to alternately turn on and off every half cycle from the high-voltage oscillation drive circuit 125.

In other words, as the switching operation of the high voltage generating circuit according to this configuration, first, power is supplied to the high voltage oscillation driving circuit 125 through the resistor 131 at + B voltage, and when + B voltage is supplied to the high voltage generating circuit, In the oscillation drive circuit 125, the positive drive pulse is supplied to the switching element Qa3. The positive resonant current is supplied to the resonant capacitor 129 and the primary winding Lb0 of the high voltage transformer 128 through the switching element Qa3.

Next, a negative driving pulse is supplied to the switching element Qa3. On the contrary, a positive driving pulse of the switching element Qa4 is supplied, and the switching element Qa3 is suddenly turned off while the switching element Qa4 is turned off. It is turned on. As a result, the negative resonant current is supplied to the resonant capacitor 129 and the primary winding Lb0 of the high voltage transformer 128 through the switching element Qa4. By repeating this operation, the high voltage transformer 128 is excited by the series resonant current, and the alternating output voltage is taken out from the high voltage windings Lb1 to Lb9 wound on the secondary side of the high voltage transformer 128.

In addition, the windings Lb1 to Lb9 are connected in series with the windings Lb6 to Lb9 and the diodes Db6 to Db9 so as to perform full-wave rectification with respect to the alternating voltage of the government. ) And the diodes Da1 to Db5 are connected in series so as to be reverse polarity. The winding Lb5 having one end opened is wound around the connection portion, and an equivalent smoothing capacitor is provided to perform a series phase-up of the rectified voltages obtained by the windings Lb1 to Lb4 and the windings Lb6 to Lb9. 132 is configured to obtain a high voltage output voltage EHT.

The voltage increase of the high voltage output voltage EHT obtained by the high voltage windings Lb1 to Lb9 is performed as follows, for example, in the same manner as in the case of the equivalent circuit of FIG. 10 described above. That is, in this high voltage generation circuit, when the resonance frequency of the series resonance circuit composed of the series resonance capacitor 129, the choke coil 130, and the primary winding Lb0 of the high voltage transformer 128 is set to f0, this resonance is achieved. The switching frequency fsw1 of the switching circuit composed of the half-bridge converter is set higher than the frequency f01.

For example, when the luminance of the image displayed on the cathode ray tube increases, and as a result, the high voltage load changes, the high voltage output voltage EHT changes so as to decrease. The high-voltage fluctuation is taken out of the high-voltage detection circuit composed of the resistors 133 and 134, and the control signal obtained from the control circuit 127 is sent to the high-voltage oscillation driving circuit 125, and the high-voltage oscillation driving circuit 125 is in accordance with this voltage. The operating frequency of the driving pulse output from the controller is controlled to decrease. As a result, when the switching frequency of the switching elements Qa3 and Qa4 is fsw1, this switching frequency fsw1 falls.

On the contrary, if the brightness of the image displayed on the cathode ray tube decreases and, as a result, the high voltage load is changed to decrease, the high voltage output voltage EHT is changed to increase. The voltage fluctuation is taken out of the voltage detection circuit composed of the resistors 133 and 134, and the control signal obtained from the control circuit 127 is sent to the oscillation drive circuit 125, and the high voltage oscillation drive circuit 125 The operating frequency of the output drive pulse is controlled to increase. As a result, the switching frequencies fsw1 of the switching elements Qa3 and Qa4 rise.

Therefore, in the setting of the high voltage generation circuit described above, when the brightness of the image displayed on the cathode ray tube increases and the high pressure load increases, the high voltage output voltage EHT is changed to decrease. For this reason, the switching frequency fsw is controlled to be lowered. However, at this time, the switching frequency fsw1 is close to the resonance frequency f01 of the series resonant circuit. As a result, the exciting current flowing through the primary winding Lb0 By increasing, the constant voltage is attained.

On the contrary, when the luminance of the image displayed on the cathode ray tube decreases, and as a result, the high voltage load is changed to decrease, the high voltage output voltage EHT changes to increase. For this reason, the switching frequency fsw1 is controlled to increase, and the switching frequency fsw1 is separated from the resonance frequency f01 of the series resonant circuit. As a result, the exciting current flowing through the primary winding Lb0 is suppressed. Therefore, the constant voltage can be increased.

Further, the high voltage transformer 128 has a primary winding Lb0 to which the above-mentioned excitation current is supplied, and a high voltage winding Lb1 to Lb9 for obtaining a high voltage output voltage EHT for supplying an anode voltage to a cathode ray tube as a secondary winding. At the same time, the secondary winding Lc1 which obtains the voltage E1 used as the detection voltage for the protection circuit is recommended. The alternating output voltage taken out from the secondary winding Lc1 of the high voltage transformer 128 is supplied to the smoothing capacitor 135 through the rectifying diode Dc1 and used as the detection voltage for the protection circuit. The voltage E1 to be taken out is taken out.

FIG. 13 also shows a block diagram of the entire structure of a conventional apparatus including the above-described isolated switching power supply circuit, horizontal deflection circuit and high voltage generating circuit. In Fig. 13, the rectified smoothing voltage obtained at both ends of the smoothing capacitor as a charging current is the rectified current obtained by rectifying the commercial AC power supply in the AC rectifying smoothing circuit 301 as the operating power source, and is obtained by the oscillation driving circuit 302. A switching operation is performed to the converter circuit 303 by using a drive pulse to excite the converter transformer 304, and take out an output voltage from the converter transformer 304.

Using this extracted output voltage, a switching operation is performed to the horizontal output circuit 306 using a drive pulse obtained from the horizontal oscillation drive circuit 305 to supply a deflection current to the horizontal deflection yoke 307. At the same time, the output voltage from the converter transformer 304 is supplied to the control circuit 308, and the control signal from this control circuit 308 is supplied to the oscillation drive circuit 302, and from the converter transformer 304. The output voltage is stabilized.

The high voltage transformer 311 is excited by switching to the high voltage output circuit 310 using a drive pulse obtained from the high voltage oscillation drive circuit 309 using the output voltage drawn out from the converter transformer 304. A high voltage is generated in the high voltage transformer 311 to supply a high voltage to the anode of the cathode ray tube 312. At the same time, the output voltage of the high voltage transformer 311 is supplied to the control circuit 313, and the control signal from this control circuit 313 is supplied to the high voltage oscillation drive circuit 309, and from the high voltage transformer 311. The output voltage is stabilized.

In this manner, the + B voltage, the high voltage, and other voltages are formed. However, in the above-described conventional switching power supply device, there is a need to improve in terms of more economical and effective utilization of energy resources. That is, the first is a problem of power loss of the switching circuit portion, the second is a problem of the conversion efficiency of the switching converter output transformer. Below, the problem of these two points is demonstrated.

In other words, the switching power supply apparatus has a circuit configuration including a power supply circuit portion having a function for supplying a plurality of constant voltage output voltages and a high voltage generation circuit portion for obtaining high-precision high-voltage load characteristics as a first task. . For this reason, the switching circuit section must be configured in two systems. In this case, the separate installation of the high-voltage generator circuit is very advantageous in terms of characteristics, but as a result, there are disadvantages in that the circuit configuration becomes complicated and problems incurring an increase in power loss of the switching circuit section.

In addition, the switching power supply device has an isolated converter transformer for insulation by earth ground in the power supply circuit section, and a non-isolated high voltage transformer such as a flyback transformer section in the high voltage generation circuit section. For this reason, it is necessary to set it as the structure which doubles an output converter transformer. As a result, in the configuration in which the high voltage output voltage is taken out by using a switching means that performs switching operation using the rectified smoothing voltage obtained from a commercial AC power supply, the DC / DC conversion efficiency is poor, thereby reducing power consumption. To have.

The present application has been made in view of such a point, and the problem to be solved is that in the above-described conventional switching power supply device, the problem of power loss in the first switching circuit section, and the conversion efficiency of the switching converter output transformer section in the second aspect. I had a problem.

For this reason, in the present invention, switching means for reducing the output loss of the switching power supply unit and improving the conversion efficiency, that is, switching connected to the switching output circuit which operates the switching output circuit for performing the switching operation at low loss and performs the switching operation. By adopting a control means by inductance control capable of operating at low frequency and in frequency control, this makes it possible to provide a practical switching power supply operation.

(Example)

That is, in the present invention, the switching means for performing the switching operation using the DC voltage as the operating power source, the oscillation driving means connected to the switching means for driving the switching operation at an arbitrary frequency, and the resonance driving is performed by the switching operation of the switching means. First control means for controlling the oscillation frequency of the oscillation drive means by using the control signal obtained from the primary winding and the first rectifying circuit output connected to the first secondary winding for the primary winding; And a second control means for controlling the inductance of the saturable reactor using the control signal obtained from the second rectifier circuit output connected to the second secondary winding.

In the present invention, a switching means for performing a switching operation using a DC voltage as an operating power source, an oscillation drive means connected to the switching means for driving the switching operation at an arbitrary frequency, and a resonance drive by the switching operation of the switching means. Oscillation of the oscillation drive means by using a control signal obtained from a first primary winding constituting the first converter transformer and a first rectifying circuit output connected to the first secondary winding to the first primary winding. The first control means for controlling the frequency, the second primary winding which is provided in parallel with respect to the first primary winding, and constitutes the second converter transformer, and the cannon installed in series with the second primary winding. And a second control means for controlling the inductance of the saturable reactor by using a control signal obtained from a second rectifying circuit output connected to the second secondary winding to the second primary winding. It will be good.

EMBODIMENT OF THE INVENTION Hereinafter, although this invention is demonstrated with reference to drawings, FIG. 1 is a block diagram which shows the structure of 1st Embodiment of the switching power supply apparatus which applied this invention.

In Fig. 1, a commercial AC power supply 10 is connected to a smoothing capacitor 12 via a diode bridge rectifying circuit 11. The negative electrode terminal of the capacitor 12 is grounded, the positive electrode terminal is connected to the oscillation drive circuit 14 through the resistor 13, and the positive electrode terminal of the capacitor 12 is connected to, for example, a power-MOS-FET. It is grounded through the switching circuit part 15 which becomes a series circuit of the same switching elements Q1 and Q2. These switching elements Q1 and Q2 are driven by the oscillation drive circuit 14 to alternately conduct at a predetermined frequency.

In addition, the switching circuit section 15 constitutes a half bridge circuit, the positive electrode terminal of the capacitor 12 is connected to the drain of the switching element Q1, and the source of the switching element Q2 is grounded. The damper diodes D1 and D2 are connected in parallel to the switching elements Q1 and Q2, respectively. The connection point between the source of the switching element Q1 and the drain of the switching element Q2 is grounded through the primary winding L1 of the resonant capacitor 16, the choke coil 17, and the converter transformer 18. do.

As a result, a resonant current inverted in accordance with the oscillation frequency of the oscillation drive circuit 14 described above flows through the primary winding L1 of the converter transformer 18, and a so-called current resonant converter power supply circuit is constructed. . As the switching operation of the power supply circuit according to this configuration, when the commercial AC power supply 10 is first supplied, the positive drive pulse is supplied to the switching element Q1 from the oscillation drive circuit 14. The positive resonant current is supplied to the primary winding L1 wound on the primary side of the resonant capacitor 16, the choke coil 17, and the converter transformer 18 through the switching element Q1.

Next, the negative driving pulse is supplied to the switching element Q1, the positive driving pulse is supplied to the switching element Q2 on the contrary, the switching element Q1 is suddenly turned off and the switching element Q2 is turned on. Becomes As a result, a negative resonant current is supplied to the primary capacitor L1 of the resonant capacitor 16, the choke coil 17, and the converter transformer 18 through the switching element Q2, and the operation is repeated to thereby produce a series resonant current. The converter transformer 18 is excited by this, and the AC output voltage is taken out from each winding wound on the secondary side of the transformer 18.

The converter transformer 18 is of an insulating type, and a primary winding L1 to which an excitation current is supplied is provided on the primary side as described above. On the secondary side of the converter transformer 18, a secondary winding L2 for obtaining a + B voltage mainly used as a power supply voltage of a horizontal deflection circuit, and two for obtaining other voltages (voltage values E2 to E4). High voltage windings L6 to L14 equipped with secondary windings L3 to L5, a rectifying circuit for obtaining a high voltage output voltage EHT for supplying the anode voltage of the cathode ray tube as the secondary winding, and a detection voltage for the protection circuit. The secondary winding L15 for obtaining the voltage E1 to be used is provided.

Here, the high voltage windings L6 to L14 are connected in series with the windings L11 to L14 and the diodes D11 to D14 so as to perform full-wave rectification with respect to the alternating voltage of the government. The windings L6 to L9 are connected to the winding L11. The diodes D6 to D10 are connected in series so as to be reverse polarity with ˜L14, and are then connected to each other. In this connection, a winding L10 of which one end is opened is recommended. An equivalent smoothing capacitor is provided to stack the rectified voltage obtained in series with the windings L6 to L9 and the windings L11 to L14. It is configured to obtain the high voltage output voltage EHT through the capacitor 19.

The constant voltage of the high voltage output voltage EHT obtained by this high voltage winding is performed as follows. For example, the input voltage value of the commercial AC power supply 10 decreases, or the luminance of the image displayed on the cathode ray tube increases, and as a result, the high voltage load increases. In this case, the high voltage output voltage EHT fluctuates so as to decrease. The voltage fluctuation is taken out of the voltage detection circuit composed of the resistors 20 and 21, and the oscillation drive circuit 14 is passed through the photocoupler 23 for insulating the constant voltage control system from the control signal obtained from the control circuit 22. To feed.

In accordance with this control signal, the operation frequency of the drive pulse output from the oscillation drive circuit 14 is controlled to decrease. As a result, when the switching frequencies of the switching elements Q1 and Q2 constituting the switching circuit unit 15 are fsw2, the switching frequency fsw2 is lowered. Here, in the above-described circuit, the switching circuit portion constituted by the half-bridge type converter rather than the resonance frequency of the series resonant circuit composed of the resonance capacitor 16, the choke coil 17, and the primary winding L1 of the converter transformer 18. The switching frequency fsw2 of (15) is set high.

For this reason, in the above-described case, when the luminance of the image displayed on the cathode ray tube increases and the high voltage load increases, the high voltage output voltage EHT is changed to decrease and the switching frequency fsw2 is controlled to decrease. If the resonant frequency of f02 is f02, the switching frequency fsw2 is close to the resonant frequency f02. As a result, the exciting current flowing through the primary winding L1 of the converter transformer 18 increases, so that the constant voltage of the high voltage output voltage EHT obtained from the high voltage winding is achieved.

On the contrary, if the commercial AC input voltage rises or if the brightness of the image displayed on the cathode ray tube decreases and, as a result, the voltage changes to reduce the high pressure load, the high voltage output voltage EHT increases. As described above, the control signal due to the voltage variation is sent to the oscillation drive circuit 14 through the photocoupler 23, and the operating frequency of the drive pulse output from the oscillation drive circuit 14 increases according to this voltage. Controlled to. As a result, the switching frequency fsw2 of the switching elements Q1 and Q2 rises.

In other words, when the brightness of the image displayed on the cathode ray tube decreases and the high voltage load is thereby changed, the high voltage output voltage EHT fluctuates so as to increase so that the switching frequency fsw2 is controlled so as to increase. The switching frequency fsw2 is separated from the resonance frequency f02 of the furnace. As a result, the exciting current flowing through the primary winding L1 of the converter transformer 18 is suppressed, whereby the constant voltage of the high voltage output voltage EHT obtained from the high voltage winding can be achieved.

Next, in the secondary windings L2, L3, L4, L5, rectifying circuits (diodes) 24, 25, 26, 27 and smoothing circuits (capacitors) 28, 29 for extracting the DC voltage from the alternating output voltage, respectively. , 30, 31 are connected. In this way, in the secondary windings L2, L3, L4, and L5 of the converter transformer 18, the so-called + B voltage (voltage value E0) and the respective signal systems which become voltage voltages of the horizontal deflection circuit and the high-voltage generating circuit, respectively. Other voltages (voltage values) E2, E3, and E4 used as power supply voltages of the circuit are taken out.

Then, the voltage increase of the + B voltage (voltage value E0) taken out from the secondary winding L2 of the converter transformer 18 is performed as follows. That is, the saturable reactor 32 is connected in series to the secondary winding L2 of this converter transformer 18 as a means for performing constant voltage control. By controlling the inductance of the saturable reactor 32, a method of controlling the + B voltage taken out of the secondary winding L2 is taken.

The saturable reactor 32 is composed of orthogonal saturable reactors, for example, having a control winding NC and a controlled winding NR as shown in FIG. 2. The control winding NR of the saturable reactor 32 is connected in series to the secondary winding L2 of the converter transformer 18, and the control winding NC detects a voltage variation of the + B voltage. Control output flows according to signal. Thereby, the inductance of the controlled winding NR connected in series with the secondary winding L2 is comprised so that it may be controlled.

That is, in FIG. 1, for example, when the output voltage E0 rises, when this output voltage E0 is detected by the detection resistors 33 and 34, and the detection voltage rises above the reference voltage 35, The output of the inversion comparison amplifier 36 decreases, and the collector current of the control transistor 37 decreases. This collector current controls the inductance of the controlled winding NR of the saturable reactor 32 as a control current, and in this case, the inductance of the controlled winding NR increases. As a result, the output voltage E0 is suppressed by the inductance control.

On the contrary, when output voltage E0 falls, the detection voltage of this output voltage E0 falls below the reference voltage 35, and the output of the inversion comparison amplifier 36 rises. Thereby, the collector current of the control transistor 37 increases, and this collector current controls the inductance of the controlled winding NR of the saturable reactor 32 as a control current, and in this case, the controlled winding NR ) To reduce the inductance. As a result, the output voltage E0 is increased by inductance control. As a result, the voltage of + B taken out from the secondary winding L2 can be increased.

In this manner, the high voltage output voltage EHT and the + B voltage (voltage value E0) are increased. Similarly, other voltages (voltage values E2, E3, and E4) taken out from the secondary windings L3, L4, and L5 of the converter transformer 18 are also similarly outlined and regulated by the so-called cross regulation. . In addition, the alternating output voltage taken out from the secondary winding L15 of the converter transformer 18 is supplied to the smoothing condenser wire 38 through the rectifying diode D15, and used as the detection voltage for the protection circuit. The voltage E1 is taken out.

3, the whole structure of the switching power supply apparatus containing the above-mentioned isolated switching power supply circuit, the horizontal deflection circuit, and the high voltage generation circuit is shown in block diagram. In Fig. 3, the rectified current obtained by rectifying the commercial AC power supply in the AC rectification smoothing circuit 401 is a charging current, and the rectified smoothing voltage obtained at both ends of the smoothing capacitor is used as the operation power supply, and the oscillation driving circuit 402 is obtained. The converter transformer 404 is excited by causing the converter circuit 403 to perform a switching operation using a drive pulse.

As a result, the converter transformer 404 takes out the high voltage output voltage EHT, the + B voltage, and other output voltages. The high voltage generated by the converter transformer 404 is supplied to the anode of the cathode ray tube 405, and the high voltage is supplied to the control circuit 406, and the control signal from the control circuit 406 is oscillating drive circuit. Supplied to 402, stabilization of the high voltage output voltage EHT is performed in the converter transformer 404.

In addition, the output voltage from the converter transformer 404 is supplied to the control circuit 407 including the saturable reactor 32 described above, and the control signal from the control circuit 407 is supplied to the converter transformer 404. The output voltage is stabilized. Using this stabilized output voltage, a switching operation is performed to the horizontal output circuit 409 using a drive pulse obtained from the horizontal oscillation drive circuit 408 to supply a deflection current to the horizontal deflection yoke 410.

Therefore, in this apparatus, a means for reducing the power loss of the switching power supply unit to improve the conversion efficiency, that is, a switching frequency connected to the switching output circuit for performing the switching operation, with low loss operating the switching output circuit for performing the switching operation. By adopting a control means by inductance control capable of performing control and low loss operation, it is possible to provide a switching power supply which is practically provided.

As a result, according to the present invention, the conventional switching power supply device has a problem of power loss in the first switching circuit section and a conversion efficiency in the second switching converter output transformer section. You can also eliminate it.

Next, a second embodiment of the present invention will be described with reference to FIG. In this second embodiment, the converter transformer is composed of a plurality of insulated converter transformers.

That is, in Fig. 4, the converter transformers 18a and 18b each constitute a part of the converter transformer 18 in Fig. 1 described above. The first converter transformer 18a is a primary winding L1a to which an excitation current is supplied, and a high voltage winding for obtaining a high voltage output voltage EHT wound as a secondary winding for supplying an anode voltage of a cathode ray tube, for example. L6 to L14 and the secondary winding L15 for obtaining the voltage E1 used as the detection voltage for the protection circuit.

The second converter transformer 18b includes a primary winding L1b to which an excitation current is supplied, a + B voltage (voltage value E0) mainly used as a power supply voltage of a horizontal deflection circuit, and other voltages (voltage value E2, It consists of secondary windings L2, L3, L4, L5 for obtaining E3, E4). In this embodiment, the saturable reactor 32 for performing constant voltage control in series with the primary winding L1b of the second converter transformer 18b is connected. It is comprised similarly to other FIG. 1, and has shown the same code | symbol to the part corresponding to FIG.

In FIG. 4, the contact between the source of the switching element Q1 and the drain of the switching element Q2 so that the two switching elements Q1 and Q2 constituting the switching circuit unit 15 constitute a half bridge circuit. One end of the resonant capacitor 16 is connected in series. One end of the primary winding L1a of the first converter transformer 18a is connected to the other end of the resonant capacitor 16 via the choke coil 17, and the other end of the primary winding L1a is grounded to the source. do.

The saturable reactor 32 is grounded at the other end of the resonant capacitor 16, and one end of the primary winding L1b of the second converter transformer 18b is connected to the saturable reactor 32, and The other end of the primary winding L1b is grounded to earth. As a result, the choke coil 17 and the primary winding L1a of the first converter transformer 18a and the primary winding L1b of the saturable reactor 32 and the second converter transformer 18b form a parallel circuit. It is configured to.

As the switching operation of the power supply circuit according to the above configuration, when the commercial AC power supply 10 is first supplied, the positive drive pulse is supplied from the oscillation drive circuit 14 to the switching element Q1. As a result, the inductance value of the composite inductor which forms the series resonant circuit in the primary windings L1a and L1b of the resonant capacitor 16 and the first and second converter transformers 18a and 18b through the switching element Q1. A positive resonant current is supplied.

Next, a negative driving pulse is supplied to the switching element Q1 and a positive driving pulse is supplied to the switching element Q2. The switching element Q1 is turned off and the switching element Q2 is turned on. As a result, contrary to the above, the negative resonant current of the primary windings L1a and L1b of the resonant capacitor 16 and the first and second converter transformers 18a and 18b is supplied through the switching element Q2. By repeating this operation, the output transformer is excited by the resonant current of the government, and the alternating output voltage is taken out from the secondary windings of the first and second converter transformers 18a and 18b, respectively.

In this apparatus, the constant voltageification of the high voltage output voltage EHT taken out from the secondary windings L6 to L14 of the first converter transformer 18a is performed as follows. For example, when the commercial alternating voltage 10 is lowered or the luminance of an image displayed on the cathode ray tube is increased, the result is that the high voltage load is increased. In this case, the high voltage output voltage EHT fluctuates so as to decrease.

The voltage fluctuation is taken out of the voltage detection circuit composed of the resistors 20 and 21, and the control signal obtained from the control circuit 22 passes through the photocoupler 23 for insulating the constant voltage control system. Supplied to. The operating frequency of the drive pulse output from the oscillation drive circuit 14 is controlled in accordance with this voltage. As a result, when the switching frequency of the switching elements Q1 and Q2 is made fsw3, this switching frequency fsw3 falls.

On the contrary, when the commercial AC input voltage 10 rises, or the brightness of the image displayed on the cathode ray tube decreases, it is intended to fluctuate so that the high voltage load decreases. In this case, the high voltage output voltage EHT fluctuates to rise. As described above, the voltage fluctuation is supplied to the oscillation drive circuit 14 through the photocoupler 23, and the operating frequency of the drive pulse output from the oscillation drive circuit 14 is controlled in accordance with this voltage. As a result, the switching frequency fsw3 of the switching elements Q1 and Q2 rises.

In this power supply circuit, the switching frequency fsw3 of the switching circuit section 15 constituted by the half-bridge type converter is the primary winding of the resonant capacitor 16, the choke coil 17, and the first converter transformer 18a. It is set so as to always be higher than the resonant frequency f03 of the resonant circuit composed of L1a and the primary winding L1b of the saturable reactor 32 and the second converter transformer 18b.

Therefore, in this circuit, if the luminance of the image displayed on the cathode ray tube increases, and as a result, the high voltage load is changed to increase, the high voltage output voltage EHT is changed to decrease. For this reason, the switching frequency fsw3 is controlled to decrease, and the switching frequency fsw3 is close to the resonance frequency f03 of the series resonant circuit. As a result, the excitation current flowing through the primary winding L1a increases. Therefore, the constant voltage can be increased.

On the contrary, if the luminance of the image displayed on the cathode ray tube decreases, and as a result, the high voltage load is changed to decrease, the high voltage output voltage EHT changes to increase. For this reason, by controlling the switching frequency fsw3 to rise, the switching frequency fsw3 is separated from the resonance frequency f03 of the series resonant circuit. As a result, the excitation current flowing through the primary winding L1a is suppressed so that the constant voltage You will be angry.

On the other hand, the constant voltageification of the output voltage E0 taken out from the secondary winding L2 of the 2nd converter transformer 18b is performed as follows. That is, the second converter transformer 18b includes a primary winding L1b to which an exciting current is supplied, a secondary winding L2 for obtaining a + B voltage used as a power supply voltage of a horizontal deflection circuit, and the other. A saturable reactor 32 for constant voltage control is connected to the secondary windings L3, L4, L5 for obtaining a voltage, or to the primary winding L1b of the second converter transformer 18b. .

Here, the saturable reactor 32 is composed of a control winding NC and a controlled winding NR, and the control winding NC has a sufficient clearance from the controlled winding NR and has a recommended insulation type. It is a saturable reactor. The controlled winding NR is connected in series to the primary winding L1b of the second converter transformer 18b, and the control winding NC of the output voltage E0 taken out from the secondary winding L2 is connected to the control winding NC. In response to the voltage fluctuation, the inductance of the controlled winding NR is controlled by flowing a control current according to the control signal.

In this apparatus, the output voltage E0 taken out from the secondary winding L2 is increased in the following operation. That is, for example, when the output voltage E0 rises, the output voltage E0 is detected by the resistors 33 and 34 for detection, and when the detection voltage rises from the reference voltage 35, the inverse comparison amplifier ( The output of 36 decreases, and the collector current of the control transistor 37 decreases. As the collector current is a control current, the inductance of the controlled winding NR of the saturable reactor 32 is controlled. In this case, the inductance of the controlled winding NR increases.

As a result, the excitation current flowing in the primary winding L1b of the second converter transformer 18b is controlled by inductance control, and the constant voltage of the output voltage E0 is achieved. That is, in this case, when the output voltage E0 rises, the output of the inverting comparison amplifier 36 decreases, the collector current of the control transistor 37 decreases, and the controlled winding NR of the saturable reactor 32 is reduced. The inductance of is increased so that the excitation current flowing through the primary winding L1b of the second converter transformer 18b is controlled by inductance control to achieve a constant voltage reduction of the output voltage E0.

Next, when the output voltage E0 is lowered, the detection voltage detected by the resistors 33 and 34 is lower than the reference voltage 35, and the output of the inversion comparison amplifier 36 is raised to control transistors. The collector current of (37) is increased. The collector current controls the inductance of the controlled winding NR of the saturable reactor 32 to be reduced. As a result, the excitation current flowing through the primary winding L1b of the second converter transformer 18b is increased by inductance control, and the constant voltage of the output voltage E0 is achieved. This other operation is performed similarly to the first embodiment described above.

Therefore, also in this apparatus, a means for reducing the power loss of the switching power supply unit to improve the conversion efficiency, that is, a switching frequency connected to the switching output circuit for performing the switching operation with low loss operating the switching output circuit for performing the switching operation. By adopting a control means by inductance control capable of performing control and low loss operation, a switching power supply device provided in practical use can be provided.

As a result, according to the present invention, the conventional switching power supply device has a problem of power loss in the switching circuit section first and a conversion efficiency in the switching converter output transformer section second. You can do it.

Moreover, 3rd Embodiment of this invention is described, referring FIG. In this third embodiment, the oscillation drive circuit portion is configured with a self-shape.                     

That is, in FIG. 5, the switching circuit part 15 is comprised using bipolar transistors Qx1 and Qx2, for example. The connecting point of the emitter of the transistor Qx1, the collector of the transistor Qx2, and the resonance capacitor 16 are connected, and the excitation winding ND, the choke coil 17, and the converter of the drive transformer 40 described later are further connected. The primary winding L1 of the transformer 18 is connected in series to form a self-contained current resonant converter having a half bridge series resonant circuit.

On the other hand, in this embodiment, the transistor 40 for driving the bipolar transistors Qx1 and Qx2 constituting the switching circuit section 15 is provided. As the drive transformer 40, for example, as shown in FIG. 6, the drive windings NB1 and NB2 and the excitation winding ND, and a control winding NC for controlling inductance of each of these windings are recommended. Such as orthogonal saturation reactor is used. The drive transformer 40 may be formed in a so-called EI type or the like that is not limited to the orthogonal saturable reactor described above.

The resistor 41 and the resonant capacitor 42 are connected to one end of the drive winding NB1 on the other hand of the drive transformer 40 so as to form a series resonant circuit, and through this series resonant circuit, the switching circuit section 15 is connected. It is connected to the base of the transistor Qx1 which constitutes. The other end of the drive winding NB1 is connected to the emitter of the transistor Qx1. In addition, a damper diode 43 is provided between the base emitters of the transistors Qx1.

The drive winding NB2 on the other side of the drive transformer 40 is provided so as to be in reverse polarity with the drive winding NB1. A resistor 44 and a resonant capacitor 45 are connected to one end of the drive winding NB2 so as to form a series resonant circuit, so that the transistor Qx2 constituting the switching circuit section 15 is formed through the series resonant circuit. While connected to the base, the other side is grounded to earth. In addition, a damper diode 46 is provided between the base emitters of the transistors Qx2.

As a result, the transistors Qx1 and Qx2 constituting the switching circuit section 15 are driven in accordance with the outputs of the drive windings NB1 and NB2 of the drive transformer 40. Then, by controlling the switching frequency fsw4, which will be described later, for driving these transistors Qx1 and Qx2 to be variable, a self-contained frequency control circuit is constructed so as to achieve constant voltage control of the output voltage obtained through the inverter transformer 18 at a later stage. It is.

The switching operation of the current resonance power supply circuit according to the above configuration is performed as follows. First, when the commercial AC power supply 10 is turned on, the starting current is supplied to the base of the transistor Qx1 through the resistor 47 for starting. Considering the case where the transistor Qx1 is turned on, the rectified output voltage from the capacitor 12 is a direct current power source, and the resonant capacitor 16, the drive winding ND, and the choke coils are provided via the transistor Qx1. 17) and a positive resonant current flows through the primary winding L1 of the converter transformer 18.

When the resonance current is zero, a positive pulse is generated in the drive winding NB2 of the drive transformer 40 to turn on the transistor Qx2, and conversely, in the drive winding NB1 of the drive transformer 40, a transistor ( A negative pulse is generated to turn Qx1) off. The transistor Qx1 is turned off and the transistor Qx2 is turned on. As a result, negative resonant current flows through the resonant capacitor 16, the drive winding ND, the choke coil 17, and the primary winding L1 of the converter transformer 18 through the transistor Qx2.

In this way, the transistors Qx1 and Qx2 constituting the switching circuit section 15 alternately turn on and off in accordance with the switching frequency fsw4, so that the excitation of the government to the primary winding L1 of the converter transformer 18 is repeated. Power is supplied. As a result, a desired alternating output is taken out to the secondary winding of the converter transformer 18, respectively.

The converter transistor 18 includes the primary winding L1 to which the above-mentioned excitation power is supplied, the secondary winding L20 for obtaining a high voltage output voltage, and the secondary windings L2 to L5 and L15 for obtaining other voltages. The secondary winding L2 is connected to the secondary winding L2 as a means for performing constant voltage control of the + B voltage E0 as described above. The secondary winding L20 is connected with a multi-voltage rectifier circuit such as a cockcroft-walton circuit composed of, for example, diodes D21 to D28 and smoothing converters C21 to C28, thereby providing a high voltage output voltage EHT. It is configured to obtain.

In this apparatus, constant voltage control of the high voltage output voltage EHT is performed as follows. That is, for example, the high-voltage output voltage EHT taken out of the 8-times cockcroft Walton circuit composed of the secondary winding L20, the diodes D21 to D28, and the smoothing capacitors C21 to C28 changes to increase. If this voltage fluctuation is detected by the voltage detecting circuit composed of the resistors 20 and 21, then the collector current of the control transistor 48 is controlled to increase by the control signal obtained from the control circuit 22.

Here, one end of the control winding NC of the drive transformer 40 described above is connected to the collector of the transistor 48, and the other end thereof is connected to the voltage source 49. Therefore, the collector current is controlled to increase the control current flowing through the control winding NC of the drive transformer 40 constituted by the saturable reactor as the control current, and the drive transformer 40 becomes saturated and the drive winding NB1, NB2) acts to reduce the inductance. As a result, the oscillation frequency of the self-oscillating circuit becomes high, and the switching frequency fsw4 at this time is controlled to increase.

On the other hand, if the resonant frequency formed by the above-mentioned resonant capacitor 16, the choke coil 17, and the converter transformer 18 is set to f04, the resonant frequency f04 is the same as the above-described circuit. Since the switching frequency fsw4 is set in a higher region, the higher the switching frequency, the lower the resonance frequency fsw4 becomes. Thus, the excitation current supplied to the primary winding L1 is suppressed, and the secondary winding The constant voltage of the high voltage output voltage EHT taken out from the L20 is attained.

In addition, the constant voltageification of the output voltage E0 taken out from the secondary winding L2 of the converter transformer 18 is performed as follows. A saturable reactor 32 for performing constant voltage control is connected to the secondary winding L2. The saturable reactor 32 is composed of a control winding NC and a controlled winding NR. The controlled winding NR is connected in series to the secondary winding L2, and the control winding NC is connected. The inductance of the controlled winding NR is controlled by causing the control current according to the control signal to flow in response to the voltage variation of the output voltage E0.

In other words, the load condition of the output voltage E0 is changed to change the output voltage E0 to rise. As described above, the control winding NCD is controlled to reduce the control current by the control signal according to the voltage fluctuation. As a result, the inductance of the controlled winding NR of the saturable reactor 32 increases, and the exciting current flowing through the primary winding L2 of the converter transformer 18 is controlled by the inductance control, thereby achieving constant voltage. do. In addition, operation | movement other than that is performed similarly to 1st Embodiment mentioned above.

Therefore, also in this apparatus, means for reducing the power loss of the switching power supply unit to improve the conversion efficiency, that is, switching frequency control connected to the switching output circuit which operates the switching output circuit at low loss and performs the switching operation; It is to use the control means by inductance control which can operate with low loss, and according to this, the switching power supply apparatus provided in practical use can be provided.

As a result, according to the present invention, in the conventional switching power supply device, the problem of power loss in the first switching circuit section and the conversion efficiency in the second switching converter output transformer section can be easily solved according to the present invention. have.

Moreover, 4th Embodiment of this invention is described, referring FIG. In this embodiment, by configuring the parallel resonant circuit, the circuit operation equivalent to each of the above-described embodiments is realized in the voltage resonant switching converter circuit.

That is, in FIG. 7, the switching circuit part 15 is comprised by the switching element of 1 seat, and the resonance capacitor 51 and the damper diode 52 are connected in parallel with the switching element of the switching circuit part 15. In FIG. The rectified output voltage of the commercial AC power supply 10 is supplied to one end of the primary winding L1 of the converter transformer 18 through the choke coil 17, and the primary winding L1 of the converter transformer 18. The other end of is connected to the collector of the switching element of the switching circuit section 15.

In addition, power is supplied to the oscillation drive circuit 14 through the resistor 13, and the driving pulse is sent to the base of the switching element of the switching circuit section 15 in the oscillation drive circuit 14. By turning on and off the switching elements of the switching circuit unit 15, a resonance voltage is generated at the collector of the switching elements of the switching circuit unit 15, and a resonance current is applied to the primary winding L1 of the converter transformer 18. Supplied. Next, it is comprised similarly to embodiment of FIG. 5 mentioned above.

In this apparatus, the same operation as that in the first embodiment shown in FIG. 1 is performed for the constant voltage control of the output voltage. As described above, in the fourth embodiment, by configuring the parallel resonant circuit, the circuit operation equivalent to the above-described embodiments can be realized in the voltage resonant switching converter circuit.

Therefore, also in this apparatus, the switching frequency control connected to the switching output circuit which performs a low loss of the means which improves conversion efficiency by reducing the power loss of a switching power supply part, ie, the switching output circuit which performs a switching operation, is performed. And a control means by inductance control capable of operating at low loss. The switching power supply provided in practical use can be provided.

As a result, according to the present invention, in the conventional switching power supply device, the first problem of the output loss of the switching circuit part and the second of the conversion efficiency of the switching converter output transformer part are easily solved. It can be solved.

In this way, according to the above-described switching power supply apparatus, switching means for performing a switching operation using a DC voltage as an operating power source, oscillation drive means connected to the switching means to drive the switching operation at an arbitrary frequency, and switching operation of the switching means. First control means for controlling the oscillation frequency of the oscillation drive means by using a control signal obtained from a primary winding wound by resonance and a first rectifying circuit output connected to the primary winding of the primary winding; Second control means for controlling the inductance of the saturable reactor using a control signal obtained from a saturable reactor connected to a second secondary winding to the primary winding and a second rectifier circuit output connected to the saturable reactor. By eliminating the problem of power loss in the switching circuit section and conversion efficiency in the switching converter output transformer section, the switching is practically provided. It is capable of providing a source device.

According to the above-described switching power supply apparatus, switching means for performing a switching operation using a DC voltage as an operating power source, oscillation driving means connected to the switching means for driving the switching operation at an arbitrary frequency, and switching operation of the switching means. Oscillation drive using a control signal obtained from the first rectified circuit output connected to the first primary winding constituting the first converter transformer and the first secondary winding relative to the first primary winding First control means for controlling the oscillation frequency of the means, a second primary winding provided in parallel with the first primary winding and constituting the second converter transformer, and a second primary winding in series A second to control the inductance of the saturable reactor by using a saturable reactor provided and a control signal obtained from a second rectifier circuit output connected to the second secondary winding to the second primary winding; By matching the control means, to solve the problem of power loss problem or switching converter output conversion efficiency of the transformer portion of the switching circuit, it is possible to provide a switching power supply device equipped with practical.

In addition, this invention is not limited to the structure of said embodiment, The system of the resonance type converter may be changed suitably, and may be comprised. In addition, the high voltage rectifying circuit of the high voltage generating circuit is not limited to the configuration of the above-described embodiment, but may be a multiple winding circuit or a secondary winding of a plurality of divided high voltage transformers as shown in FIGS. 8A and 8B, a plurality of rectifying diodes, and The high-pressure rectification method composed of the capacitor may be changed as appropriate.

According to the present invention, the converter transformer is made of non-isolated type, and a rectifying smoothing means for generating a rectifying smoothing voltage as a charging current is provided as a charging current using a rectifying current obtained by rectifying an applied AC power source. The same effect can be obtained even if the direct current voltage is constituted by a switching means for performing a switching operation as the operating power source.

As described above, the present invention utilizes a resonant converter capable of a high frequency switching operation having a characteristic that switching output current waveforms and voltage waveforms are very smooth, and thus there is little switching noise or switching loss. And by using the frequency control means, the constant voltage control of the main voltage is performed, and the constant voltage control of other main output voltages is performed, and the inductance control using a saturable reactor having a characteristic of low switching noise and switching loss. It is to provide an extremely effective solution which is realized by having a combination of means and which enables the constant voltage of a plurality of output voltages with large load fluctuations by a configuration of a greatly simplified switching circuit.

As a result, a high voltage generating circuit having a large high voltage load fluctuation, a power supply circuit for supplying other voltages, a frequency control means using a resonant converter circuit with low switching noise and a low switching loss, and a saturable reactor with low operating loss are used. By simultaneously using the control means used, it is possible to obtain a high voltage output directly from the converter transformer of the power supply circuit section to achieve the convergence of the high voltage generating circuit and the power supply circuit for supplying other voltages with a simple circuit configuration. As a result, the DC / DC conversion, which has been performed in two times in which the + B voltage obtained by converting the constant voltage obtained from the converter transformer, is obtained as a power supply voltage and obtains a high voltage output from the high voltage transformer, is performed in one DC / DC conversion as described above. By doing so, it was possible to significantly improve the conversion efficiency.

As described above, the present invention comprises a resonant converter and a saturable reactor for constant voltage control, and constitutes a power supply circuit by integrating an insulated constant voltage power supply circuit and a high voltage generation circuit, thereby miniaturizing and reducing weight due to low noise, low cost, and high frequency switching operation. In addition, the switching circuit and the transformer configuration can be simplified, thereby greatly improving the conversion efficiency and increasing the power consumption of the product.

In addition, according to the invention of Claims 1 and 7, the switching output which performs the switching operation with low loss by means of reducing the power loss of the switching power supply unit to improve the conversion efficiency, that is, the switching output circuit which performs the switching operation, By adopting the switching frequency control connected to the circuit and the control means by the inductance control capable of operating at low loss, the problem of power loss in the switching circuit section and the conversion efficiency of the switching converter output transformer section can be solved, resulting in a good switching performance. A power supply can be provided.

In addition, according to the invention described in claim 2, the primary winding and the first and second secondary windings are provided in a single converter transformer, or as the primary windings, the first and second windings in parallel are respectively 1 The first and second secondary windings are paired to the primary windings, and are installed in separate converter transformers for each of the first and second primary and secondary windings, thereby causing problems of power loss in the switching circuit portion and switching converter output. It is possible to solve the problem of the conversion efficiency of the transformer unit and to provide a switching power supply which is practically provided.

Further, according to the inventions of Claims 3 and 8, the oscillation drive means comprises a drive frequency winding circuit or a drive winding for driving the switching means and a resonant path from the switching means in series. A self-contained frequency control circuit is constructed using an excitation winding and a saturable reactor having control windings for inductance control of each of these windings, thereby causing problems of power loss in the switching circuit section and conversion efficiency of the switching converter output transformer section. It is possible to provide a switching power supply which is practically provided by solving the problem.

Further, according to the inventions of Claims 4 and 9, the resonance driving by switching of the switching means is provided so that the resonance capacitor is connected in series with the primary winding, so that the switching operation of the switching means is a current resonance type, Alternatively, a switching means is connected in series with the primary winding, and a resonant capacitor is connected in parallel with the switching means, so that the switching operation of the switching means is made to be a voltage resonant type. It is possible to solve the problem of the conversion efficiency of the transformer unit and to provide a switching power supply which is practically provided.                     

Further, according to the invention of Claims 5 and 10, the first control means has a first rectifier circuit having a multi-back voltage rectification circuit configuration, and uses the control signal obtained from the multi-back voltage rectification circuit output to generate the oscillation drive means. By controlling the oscillation frequency, it is possible to solve the problem of power loss in the switching circuit section and the conversion efficiency in the switching converter output transformer section, and to provide a switching power supply having practical use.

According to the invention of Claims 6 and 11, the rectifier smoothing circuit which generates a rectified smoothing voltage as a charging current is supplied to the rectifying current obtained by rectifying a commercial AC power supply, and / or a DC voltage from the outside. By using the power supply from the direct current power supply circuit, the problem of power loss in the switching circuit section and the conversion efficiency of the switching converter output transformer section can be solved, and a switching power supply device which is practically provided can be provided.

As a result, in the conventional switching power supply device, the problems of power loss in the switching circuit section at first and the conversion efficiency in the switching converter output transformer section at second are easily solved according to the present invention. It can be solved.

Claims (11)

Switching means for performing a switching operation using a DC voltage as an operating power source; An oscillation drive means connected to the switching means to drive the switching operation at an arbitrary oscillation frequency; A primary winding driven in a resonance state by a switching operation of the switching means, First control means for controlling the oscillation frequency of the oscillation drive means by using a control signal obtained from a first rectified circuit output connected to the first secondary winding to the primary winding; A saturable reactor connected to the second secondary winding with respect to the first secondary winding; And second control means for controlling the inductance of the saturable reactor by using a control signal obtained at the output of the second rectifier circuit connected to the saturable reactor. The method of claim 1, And the first winding and the first and second windings are installed in a single converter transformer. The method of claim 1, The oscillation drive means, a switching power supply characterized in that a sasarate-excited frequency control circuit is configured. The method of claim 1, The switching power supply is characterized in that the switching means is performed by a resonant capacitor connected in series with the primary winding so that the switching operation of the switching means is performed in a current resonance type. The method of claim 1, And the first control means comprises the first rectifier circuit as a multi-back voltage rectifier circuit, and controls the oscillation frequency of the oscillation drive means by using a control signal obtained from the output of the multi-back voltage rectifier circuit. Power supply. The method of claim 1, The operation power supply is a switching power supply, characterized in that one of the power obtained in the rectified smoothing power supply circuit for generating a rectified smoothing voltage using the rectified current obtained by rectifying the commercial AC power supply as the charging current. Switching means for performing a switching operation using a DC voltage as an operating power source; An oscillation drive means connected to the switching means to drive the switching operation at an arbitrary oscillation frequency; A first primary winding which is driven in a resonance state by the switching operation of the switching means and constitutes a part of the first converter transformer; First control means for controlling the oscillation frequency of the oscillation drive means by using a control signal obtained at the output of the first rectifying circuit connected to the first secondary winding to the first primary winding; A second primary winding provided in parallel with the first primary winding and forming a part of the second converter transformer; A saturable reactor connected in series with the second primary winding; And second control means for controlling the inductance of the saturable reactor by using a control signal obtained at the output of the second rectifying circuit connected to the second secondary winding to the second primary winding. Switching power supply. The method of claim 7, wherein The oscillation drive means, a switching power supply characterized in that a sasarate-excited frequency control circuit is configured. The method of claim 7, wherein The switching power supply is characterized in that the switching means is performed by a resonant capacitor connected in series with the primary winding so that the switching operation of the switching means is performed in a current resonance type. The method of claim 7, wherein And the first control means comprises the first rectifier circuit as a multi-back voltage rectifier circuit, and controls the oscillation frequency of the oscillation drive means by using a control signal obtained from the output of the multi-back voltage rectifier circuit. Power supply. delete

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